Step |
Hyp |
Ref |
Expression |
1 |
|
requad2.a |
⊢ ( 𝜑 → 𝐴 ∈ ℝ ) |
2 |
|
requad2.z |
⊢ ( 𝜑 → 𝐴 ≠ 0 ) |
3 |
|
requad2.b |
⊢ ( 𝜑 → 𝐵 ∈ ℝ ) |
4 |
|
requad2.c |
⊢ ( 𝜑 → 𝐶 ∈ ℝ ) |
5 |
|
requad2.d |
⊢ ( 𝜑 → 𝐷 = ( ( 𝐵 ↑ 2 ) − ( 4 · ( 𝐴 · 𝐶 ) ) ) ) |
6 |
1
|
recnd |
⊢ ( 𝜑 → 𝐴 ∈ ℂ ) |
7 |
6
|
adantr |
⊢ ( ( 𝜑 ∧ 𝑥 ∈ ℝ ) → 𝐴 ∈ ℂ ) |
8 |
2
|
adantr |
⊢ ( ( 𝜑 ∧ 𝑥 ∈ ℝ ) → 𝐴 ≠ 0 ) |
9 |
3
|
recnd |
⊢ ( 𝜑 → 𝐵 ∈ ℂ ) |
10 |
9
|
adantr |
⊢ ( ( 𝜑 ∧ 𝑥 ∈ ℝ ) → 𝐵 ∈ ℂ ) |
11 |
4
|
recnd |
⊢ ( 𝜑 → 𝐶 ∈ ℂ ) |
12 |
11
|
adantr |
⊢ ( ( 𝜑 ∧ 𝑥 ∈ ℝ ) → 𝐶 ∈ ℂ ) |
13 |
|
recn |
⊢ ( 𝑥 ∈ ℝ → 𝑥 ∈ ℂ ) |
14 |
13
|
adantl |
⊢ ( ( 𝜑 ∧ 𝑥 ∈ ℝ ) → 𝑥 ∈ ℂ ) |
15 |
5
|
adantr |
⊢ ( ( 𝜑 ∧ 𝑥 ∈ ℝ ) → 𝐷 = ( ( 𝐵 ↑ 2 ) − ( 4 · ( 𝐴 · 𝐶 ) ) ) ) |
16 |
7 8 10 12 14 15
|
quad |
⊢ ( ( 𝜑 ∧ 𝑥 ∈ ℝ ) → ( ( ( 𝐴 · ( 𝑥 ↑ 2 ) ) + ( ( 𝐵 · 𝑥 ) + 𝐶 ) ) = 0 ↔ ( 𝑥 = ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∨ 𝑥 = ( ( - 𝐵 − ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ) ) ) |
17 |
|
eleq1 |
⊢ ( 𝑥 = ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) → ( 𝑥 ∈ ℝ ↔ ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∈ ℝ ) ) |
18 |
17
|
adantl |
⊢ ( ( 𝜑 ∧ 𝑥 = ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ) → ( 𝑥 ∈ ℝ ↔ ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∈ ℝ ) ) |
19 |
|
2re |
⊢ 2 ∈ ℝ |
20 |
19
|
a1i |
⊢ ( 𝜑 → 2 ∈ ℝ ) |
21 |
20 1
|
remulcld |
⊢ ( 𝜑 → ( 2 · 𝐴 ) ∈ ℝ ) |
22 |
21
|
adantr |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ( 2 · 𝐴 ) ∈ ℝ ) |
23 |
9
|
negcld |
⊢ ( 𝜑 → - 𝐵 ∈ ℂ ) |
24 |
3
|
resqcld |
⊢ ( 𝜑 → ( 𝐵 ↑ 2 ) ∈ ℝ ) |
25 |
|
4re |
⊢ 4 ∈ ℝ |
26 |
25
|
a1i |
⊢ ( 𝜑 → 4 ∈ ℝ ) |
27 |
1 4
|
remulcld |
⊢ ( 𝜑 → ( 𝐴 · 𝐶 ) ∈ ℝ ) |
28 |
26 27
|
remulcld |
⊢ ( 𝜑 → ( 4 · ( 𝐴 · 𝐶 ) ) ∈ ℝ ) |
29 |
24 28
|
resubcld |
⊢ ( 𝜑 → ( ( 𝐵 ↑ 2 ) − ( 4 · ( 𝐴 · 𝐶 ) ) ) ∈ ℝ ) |
30 |
5 29
|
eqeltrd |
⊢ ( 𝜑 → 𝐷 ∈ ℝ ) |
31 |
30
|
recnd |
⊢ ( 𝜑 → 𝐷 ∈ ℂ ) |
32 |
31
|
sqrtcld |
⊢ ( 𝜑 → ( √ ‘ 𝐷 ) ∈ ℂ ) |
33 |
23 32
|
addcld |
⊢ ( 𝜑 → ( - 𝐵 + ( √ ‘ 𝐷 ) ) ∈ ℂ ) |
34 |
33
|
adantr |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ( - 𝐵 + ( √ ‘ 𝐷 ) ) ∈ ℂ ) |
35 |
3
|
renegcld |
⊢ ( 𝜑 → - 𝐵 ∈ ℝ ) |
36 |
35
|
adantr |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → - 𝐵 ∈ ℝ ) |
37 |
32
|
adantr |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ( √ ‘ 𝐷 ) ∈ ℂ ) |
38 |
31
|
negnegd |
⊢ ( 𝜑 → - - 𝐷 = 𝐷 ) |
39 |
38
|
adantr |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → - - 𝐷 = 𝐷 ) |
40 |
39
|
eqcomd |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → 𝐷 = - - 𝐷 ) |
41 |
40
|
fveq2d |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ( √ ‘ 𝐷 ) = ( √ ‘ - - 𝐷 ) ) |
42 |
30
|
renegcld |
⊢ ( 𝜑 → - 𝐷 ∈ ℝ ) |
43 |
42
|
adantr |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → - 𝐷 ∈ ℝ ) |
44 |
|
0red |
⊢ ( 𝜑 → 0 ∈ ℝ ) |
45 |
30 44
|
ltnled |
⊢ ( 𝜑 → ( 𝐷 < 0 ↔ ¬ 0 ≤ 𝐷 ) ) |
46 |
|
ltle |
⊢ ( ( 𝐷 ∈ ℝ ∧ 0 ∈ ℝ ) → ( 𝐷 < 0 → 𝐷 ≤ 0 ) ) |
47 |
30 44 46
|
syl2anc |
⊢ ( 𝜑 → ( 𝐷 < 0 → 𝐷 ≤ 0 ) ) |
48 |
45 47
|
sylbird |
⊢ ( 𝜑 → ( ¬ 0 ≤ 𝐷 → 𝐷 ≤ 0 ) ) |
49 |
48
|
imp |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → 𝐷 ≤ 0 ) |
50 |
30
|
le0neg1d |
⊢ ( 𝜑 → ( 𝐷 ≤ 0 ↔ 0 ≤ - 𝐷 ) ) |
51 |
50
|
adantr |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ( 𝐷 ≤ 0 ↔ 0 ≤ - 𝐷 ) ) |
52 |
49 51
|
mpbid |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → 0 ≤ - 𝐷 ) |
53 |
43 52
|
sqrtnegd |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ( √ ‘ - - 𝐷 ) = ( i · ( √ ‘ - 𝐷 ) ) ) |
54 |
41 53
|
eqtrd |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ( √ ‘ 𝐷 ) = ( i · ( √ ‘ - 𝐷 ) ) ) |
55 |
|
ax-icn |
⊢ i ∈ ℂ |
56 |
55
|
a1i |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → i ∈ ℂ ) |
57 |
31
|
negcld |
⊢ ( 𝜑 → - 𝐷 ∈ ℂ ) |
58 |
57
|
sqrtcld |
⊢ ( 𝜑 → ( √ ‘ - 𝐷 ) ∈ ℂ ) |
59 |
58
|
adantr |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ( √ ‘ - 𝐷 ) ∈ ℂ ) |
60 |
56 59
|
mulcomd |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ( i · ( √ ‘ - 𝐷 ) ) = ( ( √ ‘ - 𝐷 ) · i ) ) |
61 |
43 52
|
resqrtcld |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ( √ ‘ - 𝐷 ) ∈ ℝ ) |
62 |
|
inelr |
⊢ ¬ i ∈ ℝ |
63 |
|
eldif |
⊢ ( i ∈ ( ℂ ∖ ℝ ) ↔ ( i ∈ ℂ ∧ ¬ i ∈ ℝ ) ) |
64 |
55 62 63
|
mpbir2an |
⊢ i ∈ ( ℂ ∖ ℝ ) |
65 |
64
|
a1i |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → i ∈ ( ℂ ∖ ℝ ) ) |
66 |
30
|
lt0neg1d |
⊢ ( 𝜑 → ( 𝐷 < 0 ↔ 0 < - 𝐷 ) ) |
67 |
|
ltne |
⊢ ( ( 0 ∈ ℝ ∧ 0 < - 𝐷 ) → - 𝐷 ≠ 0 ) |
68 |
44 67
|
sylan |
⊢ ( ( 𝜑 ∧ 0 < - 𝐷 ) → - 𝐷 ≠ 0 ) |
69 |
42
|
adantr |
⊢ ( ( 𝜑 ∧ 0 < - 𝐷 ) → - 𝐷 ∈ ℝ ) |
70 |
|
ltle |
⊢ ( ( 0 ∈ ℝ ∧ - 𝐷 ∈ ℝ ) → ( 0 < - 𝐷 → 0 ≤ - 𝐷 ) ) |
71 |
44 42 70
|
syl2anc |
⊢ ( 𝜑 → ( 0 < - 𝐷 → 0 ≤ - 𝐷 ) ) |
72 |
71
|
imp |
⊢ ( ( 𝜑 ∧ 0 < - 𝐷 ) → 0 ≤ - 𝐷 ) |
73 |
|
sqrt00 |
⊢ ( ( - 𝐷 ∈ ℝ ∧ 0 ≤ - 𝐷 ) → ( ( √ ‘ - 𝐷 ) = 0 ↔ - 𝐷 = 0 ) ) |
74 |
69 72 73
|
syl2anc |
⊢ ( ( 𝜑 ∧ 0 < - 𝐷 ) → ( ( √ ‘ - 𝐷 ) = 0 ↔ - 𝐷 = 0 ) ) |
75 |
74
|
bicomd |
⊢ ( ( 𝜑 ∧ 0 < - 𝐷 ) → ( - 𝐷 = 0 ↔ ( √ ‘ - 𝐷 ) = 0 ) ) |
76 |
75
|
necon3bid |
⊢ ( ( 𝜑 ∧ 0 < - 𝐷 ) → ( - 𝐷 ≠ 0 ↔ ( √ ‘ - 𝐷 ) ≠ 0 ) ) |
77 |
68 76
|
mpbid |
⊢ ( ( 𝜑 ∧ 0 < - 𝐷 ) → ( √ ‘ - 𝐷 ) ≠ 0 ) |
78 |
77
|
ex |
⊢ ( 𝜑 → ( 0 < - 𝐷 → ( √ ‘ - 𝐷 ) ≠ 0 ) ) |
79 |
66 78
|
sylbid |
⊢ ( 𝜑 → ( 𝐷 < 0 → ( √ ‘ - 𝐷 ) ≠ 0 ) ) |
80 |
45 79
|
sylbird |
⊢ ( 𝜑 → ( ¬ 0 ≤ 𝐷 → ( √ ‘ - 𝐷 ) ≠ 0 ) ) |
81 |
80
|
imp |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ( √ ‘ - 𝐷 ) ≠ 0 ) |
82 |
61 65 81
|
recnmulnred |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ( ( √ ‘ - 𝐷 ) · i ) ∉ ℝ ) |
83 |
|
df-nel |
⊢ ( ( ( √ ‘ - 𝐷 ) · i ) ∉ ℝ ↔ ¬ ( ( √ ‘ - 𝐷 ) · i ) ∈ ℝ ) |
84 |
82 83
|
sylib |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ¬ ( ( √ ‘ - 𝐷 ) · i ) ∈ ℝ ) |
85 |
60 84
|
eqneltrd |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ¬ ( i · ( √ ‘ - 𝐷 ) ) ∈ ℝ ) |
86 |
54 85
|
eqneltrd |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ¬ ( √ ‘ 𝐷 ) ∈ ℝ ) |
87 |
37 86
|
eldifd |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ( √ ‘ 𝐷 ) ∈ ( ℂ ∖ ℝ ) ) |
88 |
36 87
|
readdcnnred |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ( - 𝐵 + ( √ ‘ 𝐷 ) ) ∉ ℝ ) |
89 |
|
df-nel |
⊢ ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) ∉ ℝ ↔ ¬ ( - 𝐵 + ( √ ‘ 𝐷 ) ) ∈ ℝ ) |
90 |
88 89
|
sylib |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ¬ ( - 𝐵 + ( √ ‘ 𝐷 ) ) ∈ ℝ ) |
91 |
34 90
|
eldifd |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ( - 𝐵 + ( √ ‘ 𝐷 ) ) ∈ ( ℂ ∖ ℝ ) ) |
92 |
|
2cnd |
⊢ ( 𝜑 → 2 ∈ ℂ ) |
93 |
|
2ne0 |
⊢ 2 ≠ 0 |
94 |
93
|
a1i |
⊢ ( 𝜑 → 2 ≠ 0 ) |
95 |
92 6 94 2
|
mulne0d |
⊢ ( 𝜑 → ( 2 · 𝐴 ) ≠ 0 ) |
96 |
95
|
adantr |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ( 2 · 𝐴 ) ≠ 0 ) |
97 |
22 91 96
|
cndivrenred |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∉ ℝ ) |
98 |
|
df-nel |
⊢ ( ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∉ ℝ ↔ ¬ ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∈ ℝ ) |
99 |
97 98
|
sylib |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ¬ ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∈ ℝ ) |
100 |
99
|
ex |
⊢ ( 𝜑 → ( ¬ 0 ≤ 𝐷 → ¬ ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∈ ℝ ) ) |
101 |
100
|
con4d |
⊢ ( 𝜑 → ( ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∈ ℝ → 0 ≤ 𝐷 ) ) |
102 |
101
|
adantr |
⊢ ( ( 𝜑 ∧ 𝑥 = ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ) → ( ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∈ ℝ → 0 ≤ 𝐷 ) ) |
103 |
18 102
|
sylbid |
⊢ ( ( 𝜑 ∧ 𝑥 = ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ) → ( 𝑥 ∈ ℝ → 0 ≤ 𝐷 ) ) |
104 |
103
|
ex |
⊢ ( 𝜑 → ( 𝑥 = ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) → ( 𝑥 ∈ ℝ → 0 ≤ 𝐷 ) ) ) |
105 |
|
eleq1 |
⊢ ( 𝑥 = ( ( - 𝐵 − ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) → ( 𝑥 ∈ ℝ ↔ ( ( - 𝐵 − ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∈ ℝ ) ) |
106 |
105
|
adantl |
⊢ ( ( 𝜑 ∧ 𝑥 = ( ( - 𝐵 − ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ) → ( 𝑥 ∈ ℝ ↔ ( ( - 𝐵 − ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∈ ℝ ) ) |
107 |
23 32
|
subcld |
⊢ ( 𝜑 → ( - 𝐵 − ( √ ‘ 𝐷 ) ) ∈ ℂ ) |
108 |
107
|
adantr |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ( - 𝐵 − ( √ ‘ 𝐷 ) ) ∈ ℂ ) |
109 |
36 87
|
resubcnnred |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ( - 𝐵 − ( √ ‘ 𝐷 ) ) ∉ ℝ ) |
110 |
|
df-nel |
⊢ ( ( - 𝐵 − ( √ ‘ 𝐷 ) ) ∉ ℝ ↔ ¬ ( - 𝐵 − ( √ ‘ 𝐷 ) ) ∈ ℝ ) |
111 |
109 110
|
sylib |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ¬ ( - 𝐵 − ( √ ‘ 𝐷 ) ) ∈ ℝ ) |
112 |
108 111
|
eldifd |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ( - 𝐵 − ( √ ‘ 𝐷 ) ) ∈ ( ℂ ∖ ℝ ) ) |
113 |
22 112 96
|
cndivrenred |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ( ( - 𝐵 − ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∉ ℝ ) |
114 |
|
df-nel |
⊢ ( ( ( - 𝐵 − ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∉ ℝ ↔ ¬ ( ( - 𝐵 − ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∈ ℝ ) |
115 |
113 114
|
sylib |
⊢ ( ( 𝜑 ∧ ¬ 0 ≤ 𝐷 ) → ¬ ( ( - 𝐵 − ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∈ ℝ ) |
116 |
115
|
ex |
⊢ ( 𝜑 → ( ¬ 0 ≤ 𝐷 → ¬ ( ( - 𝐵 − ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∈ ℝ ) ) |
117 |
116
|
con4d |
⊢ ( 𝜑 → ( ( ( - 𝐵 − ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∈ ℝ → 0 ≤ 𝐷 ) ) |
118 |
117
|
adantr |
⊢ ( ( 𝜑 ∧ 𝑥 = ( ( - 𝐵 − ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ) → ( ( ( - 𝐵 − ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∈ ℝ → 0 ≤ 𝐷 ) ) |
119 |
106 118
|
sylbid |
⊢ ( ( 𝜑 ∧ 𝑥 = ( ( - 𝐵 − ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ) → ( 𝑥 ∈ ℝ → 0 ≤ 𝐷 ) ) |
120 |
119
|
ex |
⊢ ( 𝜑 → ( 𝑥 = ( ( - 𝐵 − ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) → ( 𝑥 ∈ ℝ → 0 ≤ 𝐷 ) ) ) |
121 |
104 120
|
jaod |
⊢ ( 𝜑 → ( ( 𝑥 = ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∨ 𝑥 = ( ( - 𝐵 − ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ) → ( 𝑥 ∈ ℝ → 0 ≤ 𝐷 ) ) ) |
122 |
121
|
com23 |
⊢ ( 𝜑 → ( 𝑥 ∈ ℝ → ( ( 𝑥 = ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∨ 𝑥 = ( ( - 𝐵 − ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ) → 0 ≤ 𝐷 ) ) ) |
123 |
122
|
imp |
⊢ ( ( 𝜑 ∧ 𝑥 ∈ ℝ ) → ( ( 𝑥 = ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∨ 𝑥 = ( ( - 𝐵 − ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ) → 0 ≤ 𝐷 ) ) |
124 |
16 123
|
sylbid |
⊢ ( ( 𝜑 ∧ 𝑥 ∈ ℝ ) → ( ( ( 𝐴 · ( 𝑥 ↑ 2 ) ) + ( ( 𝐵 · 𝑥 ) + 𝐶 ) ) = 0 → 0 ≤ 𝐷 ) ) |
125 |
124
|
rexlimdva |
⊢ ( 𝜑 → ( ∃ 𝑥 ∈ ℝ ( ( 𝐴 · ( 𝑥 ↑ 2 ) ) + ( ( 𝐵 · 𝑥 ) + 𝐶 ) ) = 0 → 0 ≤ 𝐷 ) ) |
126 |
35
|
adantr |
⊢ ( ( 𝜑 ∧ 0 ≤ 𝐷 ) → - 𝐵 ∈ ℝ ) |
127 |
30
|
adantr |
⊢ ( ( 𝜑 ∧ 0 ≤ 𝐷 ) → 𝐷 ∈ ℝ ) |
128 |
|
simpr |
⊢ ( ( 𝜑 ∧ 0 ≤ 𝐷 ) → 0 ≤ 𝐷 ) |
129 |
127 128
|
resqrtcld |
⊢ ( ( 𝜑 ∧ 0 ≤ 𝐷 ) → ( √ ‘ 𝐷 ) ∈ ℝ ) |
130 |
126 129
|
readdcld |
⊢ ( ( 𝜑 ∧ 0 ≤ 𝐷 ) → ( - 𝐵 + ( √ ‘ 𝐷 ) ) ∈ ℝ ) |
131 |
19
|
a1i |
⊢ ( ( 𝜑 ∧ 0 ≤ 𝐷 ) → 2 ∈ ℝ ) |
132 |
1
|
adantr |
⊢ ( ( 𝜑 ∧ 0 ≤ 𝐷 ) → 𝐴 ∈ ℝ ) |
133 |
131 132
|
remulcld |
⊢ ( ( 𝜑 ∧ 0 ≤ 𝐷 ) → ( 2 · 𝐴 ) ∈ ℝ ) |
134 |
95
|
adantr |
⊢ ( ( 𝜑 ∧ 0 ≤ 𝐷 ) → ( 2 · 𝐴 ) ≠ 0 ) |
135 |
130 133 134
|
redivcld |
⊢ ( ( 𝜑 ∧ 0 ≤ 𝐷 ) → ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∈ ℝ ) |
136 |
|
oveq1 |
⊢ ( 𝑥 = ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) → ( 𝑥 ↑ 2 ) = ( ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ↑ 2 ) ) |
137 |
136
|
oveq2d |
⊢ ( 𝑥 = ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) → ( 𝐴 · ( 𝑥 ↑ 2 ) ) = ( 𝐴 · ( ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ↑ 2 ) ) ) |
138 |
|
oveq2 |
⊢ ( 𝑥 = ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) → ( 𝐵 · 𝑥 ) = ( 𝐵 · ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ) ) |
139 |
138
|
oveq1d |
⊢ ( 𝑥 = ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) → ( ( 𝐵 · 𝑥 ) + 𝐶 ) = ( ( 𝐵 · ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ) + 𝐶 ) ) |
140 |
137 139
|
oveq12d |
⊢ ( 𝑥 = ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) → ( ( 𝐴 · ( 𝑥 ↑ 2 ) ) + ( ( 𝐵 · 𝑥 ) + 𝐶 ) ) = ( ( 𝐴 · ( ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ↑ 2 ) ) + ( ( 𝐵 · ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ) + 𝐶 ) ) ) |
141 |
140
|
eqeq1d |
⊢ ( 𝑥 = ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) → ( ( ( 𝐴 · ( 𝑥 ↑ 2 ) ) + ( ( 𝐵 · 𝑥 ) + 𝐶 ) ) = 0 ↔ ( ( 𝐴 · ( ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ↑ 2 ) ) + ( ( 𝐵 · ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ) + 𝐶 ) ) = 0 ) ) |
142 |
141
|
adantl |
⊢ ( ( ( 𝜑 ∧ 0 ≤ 𝐷 ) ∧ 𝑥 = ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ) → ( ( ( 𝐴 · ( 𝑥 ↑ 2 ) ) + ( ( 𝐵 · 𝑥 ) + 𝐶 ) ) = 0 ↔ ( ( 𝐴 · ( ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ↑ 2 ) ) + ( ( 𝐵 · ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ) + 𝐶 ) ) = 0 ) ) |
143 |
|
eqidd |
⊢ ( ( 𝜑 ∧ 0 ≤ 𝐷 ) → ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) = ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ) |
144 |
143
|
orcd |
⊢ ( ( 𝜑 ∧ 0 ≤ 𝐷 ) → ( ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) = ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∨ ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) = ( ( - 𝐵 − ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ) ) |
145 |
6
|
adantr |
⊢ ( ( 𝜑 ∧ 0 ≤ 𝐷 ) → 𝐴 ∈ ℂ ) |
146 |
2
|
adantr |
⊢ ( ( 𝜑 ∧ 0 ≤ 𝐷 ) → 𝐴 ≠ 0 ) |
147 |
9
|
adantr |
⊢ ( ( 𝜑 ∧ 0 ≤ 𝐷 ) → 𝐵 ∈ ℂ ) |
148 |
11
|
adantr |
⊢ ( ( 𝜑 ∧ 0 ≤ 𝐷 ) → 𝐶 ∈ ℂ ) |
149 |
92 6
|
mulcld |
⊢ ( 𝜑 → ( 2 · 𝐴 ) ∈ ℂ ) |
150 |
33 149 95
|
divcld |
⊢ ( 𝜑 → ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∈ ℂ ) |
151 |
150
|
adantr |
⊢ ( ( 𝜑 ∧ 0 ≤ 𝐷 ) → ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∈ ℂ ) |
152 |
5
|
adantr |
⊢ ( ( 𝜑 ∧ 0 ≤ 𝐷 ) → 𝐷 = ( ( 𝐵 ↑ 2 ) − ( 4 · ( 𝐴 · 𝐶 ) ) ) ) |
153 |
145 146 147 148 151 152
|
quad |
⊢ ( ( 𝜑 ∧ 0 ≤ 𝐷 ) → ( ( ( 𝐴 · ( ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ↑ 2 ) ) + ( ( 𝐵 · ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ) + 𝐶 ) ) = 0 ↔ ( ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) = ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ∨ ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) = ( ( - 𝐵 − ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ) ) ) |
154 |
144 153
|
mpbird |
⊢ ( ( 𝜑 ∧ 0 ≤ 𝐷 ) → ( ( 𝐴 · ( ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ↑ 2 ) ) + ( ( 𝐵 · ( ( - 𝐵 + ( √ ‘ 𝐷 ) ) / ( 2 · 𝐴 ) ) ) + 𝐶 ) ) = 0 ) |
155 |
135 142 154
|
rspcedvd |
⊢ ( ( 𝜑 ∧ 0 ≤ 𝐷 ) → ∃ 𝑥 ∈ ℝ ( ( 𝐴 · ( 𝑥 ↑ 2 ) ) + ( ( 𝐵 · 𝑥 ) + 𝐶 ) ) = 0 ) |
156 |
155
|
ex |
⊢ ( 𝜑 → ( 0 ≤ 𝐷 → ∃ 𝑥 ∈ ℝ ( ( 𝐴 · ( 𝑥 ↑ 2 ) ) + ( ( 𝐵 · 𝑥 ) + 𝐶 ) ) = 0 ) ) |
157 |
125 156
|
impbid |
⊢ ( 𝜑 → ( ∃ 𝑥 ∈ ℝ ( ( 𝐴 · ( 𝑥 ↑ 2 ) ) + ( ( 𝐵 · 𝑥 ) + 𝐶 ) ) = 0 ↔ 0 ≤ 𝐷 ) ) |